stu = [('B',90,85),('A',80,92),('C',85,85),('D',99,89)]
s=sorted(stu)
s1=sorted(stu,key=lambda x:x[1])
s2=sorted(stu,key=lambda x:x[2])
print(s)
print(s1)
print(s2)

def paixu(x):
    return x[1]
stu.sort(key=paixu)
print(stu)